1. Field of the Invention
This invention relates to a passenger protection apparatus for a motor vehicle with a data recording function.
2. Description of the Prior Art
An airbag unit in which the expansion is controlled in accordance with the detected weight of the passenger is disclosed in Japanese patent application provisional publication No. 11-01153. FIG. 3 shows this prior art airbag system.
The airbag unit 90 includes a gas generation unit with a plurality of inflators 92 which generate gas in response to a controller 70. The controller 70 is supplied with a crash detection signal from a crash sensor 80 and with weight detection signals from weight sensors 71 to 74. When the crash sensor detects a crash, the controller 70 determines the number of inflators to be operated in accordance with the weight determined from the weight detection signals from the weight sensors 71 to 74 and sends the result to the airbag unit 90. This operates the determined number of inflators 92 to expand the airbags 91.
This airbag unit 90 can control the expansion of the airbags to reduce the possibility of airbag side effect.
On the other hand, if a crash accident occurs, data regarding the passenger was not left because of no drive recorder like a flight recorder in an aircraft. That is, it is required to record the data regarding the passenger at the crash accident to analyze the accident.
The aim of the present invention is to provide a superior passenger protection apparatus for a motor vehicle.
According to the present invention, a first aspect of the present invention provides a passenger protection apparatus for a motor vehicle comprising:
an airbag system having a crash sensor and an airbag for generating a crash trigger signal when a crash is detected;
a passenger detection system for detecting said passenger in said motor vehicle to generate data regarding said passenger; and
data holding means having a non-volatile memory for holding said data up to said detected crash in said non-volatile memory in response to said crash trigger signal.
According to the present invention, a second aspect of the present invention provides the passenger protection apparatus based on the first aspect, wherein said passenger detection system having a passenger sensor for detecting said passenger to output a passenger sensor signal and a processing circuit for processing said passenger sensor signal to periodically output said data and an intermediate processing result obtained while said sensor signal is processed, and wherein said data holding means further holds said intermediate results up to said detected crash when said crash is detected.
According to the present invention, a third aspect of the present invention provides the passenger protection apparatus based on the first aspect, wherein said airbag system further comprises an airbag electronic control unit responsive to said crash trigger signal, said airbag being controlled by said airbag electronic control unit, and said passenger detection system comprises a passenger sensor for detecting said passenger to output a passenger sensor signal and a passenger electronic control unit for processing said passenger sensor signal to generate said data.
According to the present invention, a fourth aspect of the present invention provides the passenger protection apparatus based on the third aspect, wherein said airbag electronic control unit includes an acceleration sensor, an airbag control central processing unit, and an airbag communication interface, and said passenger detection electronic control unit includes a memory, a passenger detection central processing unit, and a passenger detection communication interface coupled to said airbag communication interface.
According to the present invention, a fifth aspect of the present invention provides the passenger protection apparatus based on the fourth aspect, wherein said airbag electronic control unit processes the outputs from said crash sensor and said acceleration sensor to generate an operation value indicative of a magnitude of crash and generates said crash trigger signal when said operation value exceeds a light crash level and sends said crash trigger signal only to said passenger detection electronic control unit and supplies said crash trigger signal to said passenger detection electronic control unit and to said airbag when said operation value exceeds a heavy crash level which is higher than said light crash level.
According to the present invention, a sixth aspect of the present invention provides the passenger protection apparatus based on the third aspect, wherein when said passenger detection electronic control unit receives said crash trigger signal, said passenger detection electronic control unit sends said data to said airbag electronic control unit, and when said airbag electronic control unit control said airbag on the basis of the received data from said passenger detection electronic control unit.
According to the present invention, a seventh aspect of the present invention provides the passenger protection apparatus based on the first aspect, wherein said data holding means holds a latest piece of said data in said non-volatile memory when said crash is detected.
According to the present invention, an eighth aspect of the present invention provides the passenger protection apparatus based on the first aspect, wherein said data holding means periodically holds said data in said non-volatile memory and inhibits rewriting said data in said non-volatile memory when said crash is detected.
According to the present invention, a ninth aspect of the present invention provides the passenger protection apparatus based on the first aspect, wherein said data holding means has a temporary memory, periodically holds said data in said temporary memory, and holds the data from said temporary memory in said non-volatile memory in response to said crash trigger signal.
According to the present invention, a tenth aspect of the present invention provides the passenger protection apparatus based on the first aspect, wherein said passenger detection system includes a sensor for detecting a load by said passenger, said data holding means holds said output of said sensor as said data.
According to the present invention, an eleventh aspect of the present invention provides the passenger protection apparatus based on the first aspect, wherein said passenger detection system includes a sensor for detecting a load by said passenger and processes an output of the sensor to have a waveform-shaped signal, said data holding means holds a result from said processed output as said data.
According to the present invention, a twelfth aspect of the present invention provides the passenger protection apparatus based on the first aspect, further comprising a processing circuit for processing a sensor signal from said crash sensor to output processing result, wherein said data holding means further holds said processing result in said non-volatile memory just after said detected crash in response to said crash trigger signal.